Enhanced in vitro anti-cancer activity of curcumin encapsulated in hydrophobically modified starch

Curcumin is a natural polyphenolic compound with anti-oxidation, anti-inflammation, and anti-cancer properties. However, these benefits of curcumin suffer from its extremely low water solubility and bioavailability. In this study, we demonstrated that hydrophobically modified starch (HMS), a food-grade biopolymer, is able to form micelles and to encapsulate curcumin. Upon encapsulation, curcumin showed increased solubility by about 1670-folds. This may be due to the hydrophobic interaction and hydrogen bonding between curcumin and HMS, as suggested by results from infrared and fluorescence spectroscopy. The synchrotron small-angle X-ray scattering results indicated that the addition of curcumin did not alter the structure of HMS, whose radius of gyration remained at 14.1 ± 0.1 nm. Moreover, encapsulated curcumin revealed enhanced in vitro anti-cancer activity compared to free curcumin. This study provides a novel food-grade encapsulation formulation to increase the bioaccessibility of curcumin.